The present application relates generally to gas turbines, and more specifically to exhaust stacks and power generation systems configured to increase the power output of gas turbines.
A combined cycle power plant (“CCPP”) includes a gas turbine, a heat recovery steam generator (“HRSG”), a steam turbine and an exhaust stack. The gas turbine includes a turbine configured to produce a rotational power output in response to an expansion of exhaust gases. The HRSG is configured to receive the exhaust gases from the gas turbine and generate steam from heat of the exhaust gases. The steam turbine is configured to produce a rotational power output in response to an expansion of the steam. The exhaust stack is configured to pass the exhaust gases from the HRSG to the atmosphere.
The gas turbine includes a compressor, a combustion region and the turbine. The compressor is configured to compress an inflow of air. The combustion region is configured to receive the compressed air, combust a mixture of the compressed air and fuel, and produce a high temperature, high pressure exhaust gases. The turbine is configured to receive the exhaust gases and rotate in response to the expansion of the exhaust gases. Accordingly, the rotational power output of the turbine is proportional to the expansion of the exhaust gases and inherent pressure drop.
Accordingly, it is desirable to provide an exhaust stack configured to reduce the local pressure drop through the exhaust stack, such that the expansion of the exhaust gases in the gas turbine is increased and hence the power output of the gas turbine is increased.